class_docstr: Abstract interface for all replay buffer implementations.
docstr: Retrieve the current fill state of the buffer.
  
  :return: Return the current fill state of the buffer.
docstr_tok: ["Retrieve","the","current","fill","state","of","the","buffer",".",":","return",":","Return","the","current","fill","state","of","the","buffer","."]
code: def __len__(self) -> int:
      """Retrieve the current fill state of the buffer.
  
      :return: Return the current fill state of the buffer.
      """
  
file_path: maze/maze/train/trainers/common/replay_buffer/replay_buffer.py
imports: from abc import abstractmethod
  from typing import Union, List
  import numpy
  from maze.core.trajectory_recording.records.structured_spaces_record import StructuredSpacesRecord
  from maze.core.trajectory_recording.records.trajectory_record import SpacesTrajectoryRecord
label_desc: Use image node_id 4 for calling the BaseReplayBuffer obj's underlying member method code with example usage: obj.__len__() without return types